neural network - Python: What Does train() Method in Pybrain Package Return? -

the link here says trainer.train() returns

a double proportional error

what mean? using backproptrainer train neural network classification. far, code has returned values less 1. mean validates training data , returns ratio of number of misclassified samples total samples?

reading the documentation seems trains on data 1 epoch. may doesn't converge in time, returns mismatch (error).

trainer.trainuntilconvergence() train on multiple epochs until converges. returns tuple of each convergence mismatch.